Definition of Kaposi sarcoma

Kaposi sarcoma: A relatively rare type of skin malignancy that tends to afflict elderly people or, those with an abnormal immune system as in AIDS. Kaposi sarcoma is a highly vascular ("angioblastic") tumor of the skin characterized by soft purplish plaques and papules that form nodules which typically start on the feet and ankles and then slowly spread across the skin of the legs, hands and arms. These tumors can also develop internally and cause severe internal bleeding.

The treatment depends on the severity of the tumor. Low dosages of radiation therapy can be effective in treating mild cases of Kaposi sarcoma. However, in more severe cases, anti-cancer drugs may be used to slow the spread of the tumor.

The tumor was first described in 1872 by the dermatologist Moritz Kaposi (Moritz Kaposi Kohn) (1837-1902). Born in Austro-Hungary, Kaposi first identified this skin cancer in older Italian and Eastern European Jewish men.

Kaposi sarcoma is now far more common and spreads more aggressively through the body among patients with AIDS. Because of the AIDS epidemic, Kaposi sarcoma left its obscure oncologic niche and entered into daily usage during in the 1990s.

Kaposi sarcoma is caused by a herpes virus -- human herpesvirus 8 (HHV-8). This virus may be transmitted by kissing. Among gay men infected with HHV-8 but without Kaposi sarcoma, the virus was found in one study in 30% of saliva samples and mouth swabs compared to only 1% of anal and genital samples and, when present, the levels of the virus were much higher in saliva than in semen. Gay men who engage in "deep kissing" -- kissing that involves much contact with saliva -- thus seem to be at higher risk of catching the virus and developing Kaposi sarcoma. It may therefore be relevant that HHV-8 is closely related to the Epstein-Barr virus, the cause of infectious mononucleosis, which can be transmitted by kissing.

The disease is also called Kaposi's sarcoma but Kaposi sarcoma is preferred since Dr. Kaposi described the tumor but did not possess it.